There has been a long-felt need for electrical receptacles or outlets which are safer; especially for children. Conventional electrical receptacles allow several possibly dangerous situations to occur. One situation results from foreign objects such as paper clips or car keys inserted into the receptacle. If the object is conductive, the person holding the foreign object acts as a conductor, thereby permitting current to flow through the object and through the person. This situation is more likely among children. While adults know better than to insert foreign objects into a receptacle, they are nevertheless not immune to the possible dangers. Adults can receive a shock by improperly holding or grasping the plug while inserting or removing it from the receptacle, since it is possible to make contact with one or more of the conducting blades while grasping the plug.
Conventional house electrical systems operate at about 110-120 volts, which is sufficient to possibly cause serious damage. Children are especially vulnerable to the effects of electricity. Consequently, a need has been recognized for safer electrical receptacles.
Some of the more common solutions in the past have utilized mechanical structures which prevent direct insertion of foreign objects. An example includes a plastic device inserted into a receptacle. This device has a flat surface which covers the face of the receptacle and several plastic blades which fit into the receptacle, thereby holding the device firm. While in place, these plugs prevent insertion of any foreign objects into the receptacle. Unfortunately, these plugs can be removed, rendering their safety efficacy nonexistent. If not removed, they present an obstacle to adults who wish to use the receptacle.
Another solution replaces the receptacle cover with a device which prevents direct insertion. One style requires the user to partially insert the plug into the receptacle, and then rotate 90.degree. to gain insertion. Another style includes the same partial insertion step, but requires a subsequent lateral translation to gain complete insertion. These structures can't completely prevent insertion of foreign objects, and can be ungainly as they are mounted in front of the receptacle in place of a conventional receptacle cover.
Other solutions include mechanical switching within a modified receptacle. For example, an inserted plug can have one or more blades that can activate such a switch. Alternatively, the receptacle can require use of a modified plug which contains one or more pins for switch activation. These solutions, unfortunately, include mechanical moving parts which are prone to wear or require the user to replace the plugs on all electrical devices. Further each of these possible solutions require user interaction. Typically, if a user is required to perform additional steps to operate a modified receptacle, they will often not bother and will eventually replace the modified receptacle with a standard outlet.
Another solution includes the use of optics; specifically, a light beam which can be interrupted by plug insertion. Typically, no power would flow while the light beam is uninterrupted, indicating that no plug is present. When a plug is inserted, the light beam is interrupted and power is allowed to flow. This solution may assist in preventing shocks caused by improperly held plugs (since the plug may need to be completely inserted to block the light beam, the user is unable to make contact with the plug blades). Unfortunately, any inserted object of a particular minimum size will block the light beam and permit power to flow. While this avoids the complexity of moving mechanical parts, insertion of most foreign objects would permit current to flow. This solution lacks the sophistication necessary to provide a receptacle which is safe for both children and adults.
A substantial need remains for electrical receptacles which are safe for children yet easy for adults to use. Preferably, such an electrical receptacle would also have the ability to prevent shocks caused by partial plug insertion.